Metal rod for reinforced concrete and process for producing said rod

ABSTRACT

Process for producing a metal rod with a high yield point and pronounced capability of adhesion, for reinforced concrete and the like, where the periphery of the rod is provided with series of spaced apart anchoring studs which have substantially the same physical properties as the core of said rod; and a process for producing such a rod by shaping and forming the starting material only by means of pressure and without subjecting the rod during the manufacture to torsion.

United States Patent 11 1 1111 3,928,998

Torres Dec. 30, 1975 1 METAL ROD FOR REINFORCED 2,552,364 5 1951Bradbury 72/198 CONCRETE AND PROCESS FOR 3,494,164 2/1970 Rehm et a1.72/187 PRODUCING SAID ROD lnventor: Hector Jose Torres, Buenos Aires,

Argentina Leonardo Francisco Aurelio, Buenos Aires, Argentina; :1 partinterest Filed: Feb. 13, 1974 Appl. No.2 442,008

Assignee:

Foreign Application Priority Data Nov. 28, 1973 Argentina 251204 US. Cl.72/185; 72/187; 72/197 Int. Cl. B21 8/00 Field of Search 72/187, 197,198, 185;

References Cited UNITED STATES PATENTS Jenks 72/187 PrimaryExaminer-Lowell A. Larson Attorney, Agent, or FirmFleit & Jacobson [57]ABSTRACT Process for producing a metal rod with a high yield point andpronounced capability of adhesion, for reinforced concrete and the like,where the periphery of the rod is provided with series of spaced apartanchoring studs which have substantially the same physical properties asthe core of said rod; and a process for producing such a rod by shapingand forming the starting material only by means of pressure and withoutsubjecting the rod during the manufacture to torsion. 1

7 Claims, 20 Drawing Figures U.S. Patent Dec. 30, 1975 Sheet 1 of23,928,998

US. Patent Dec.30, 1975 Sheet2of2 3,928,998

PROCESS FOR PRODUCING SAID ROD BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention relates to a process for producing ametal rod, preferably of iron, with a high yield point and pronouncedcapability of adhesion, for reinforced concrete and the like, as well asto a metal rod produced by such a process.

For the purpose of the present invention the expression rod is used todefine a stick-like member, which has usually a rather smallcross-sectional circular area of a diameter not larger thanapproximately 8 mm.

The expression bar is used to identify a larger, elongated metal memberthan a rod and which has, in general, a considerably higher rigiditythan the rod", as well as a larger cross-sectional area.

2. Description of the Prior Art Iron reinforcement bars used inreinforced concrete structures are well known; iron rods have smallercrosssectional areas or diameters than the bars and are used inreinforced concrete members which are subject to smaller loads, thanreinforced concrete members having bars. Both, in the event of bars aswell as rods, it is an aim to provide these reinforcing members with ahigh yield point, as well as a pronounced capability of adhesion withregard to the concrete in which they are to be embedded. In themanufacture of bars, these features are generally achieved by using asstarting material iron bars of a predetermined length and on whichperiphery longitudinal ribs are formed by rolling. These ribbed bars arethen subject to a torsional step to thereby increase the yield point andto change the shape of the longitudinal ribs into helicoidal ribs, toincrease the capability of adhesion of the resulting reinforcing memberwithin the concrete.

Upon carrying out the torsional step the yield point is particularlyincreased in the core of the bar, which is the portion whichacknowledges best the benefits of such a torsional step.

However, on the perimetral zones of such a bar and in the portionsdefining the ribs, the result as to increasing the yield point is not sogood and not so uniform as in the core portion of the bar. On the otherhand, it is to be born in mind, that the ribs are precisely the portionsof the bars which are subject to the greatest stress. Thus, it is an aimthat these ribs should havethe highest possible yield point.

The manufacturing process of such bars, cannot be a continuous process,because it includes a torsion step, where the ends of the bar have to beclamped between a pair of spaced-apart revolving heads or chucks. Thefact that the manufacturing process is an intermittent process is of nosubstantial importance in connection with the total manufacturing costof such bars, bearing in mind the weight thereof.

In the event of rods, the cost of an intermittent torsion process toincrease the yield point would have a substantial influence on the totalcost of manufacture, bearing in mind the weight of such rods. In view ofthe foregoing, it is apparent that in theevent of rods, it would be veryconvenient to provide a continuous process by means of which it ispossible to increase the yield point which at the same time should besubstantially constant throughout the entire cross-sectional area of therod. In addition, if the capability of adhesion with regard to theconcrete, of such a rod could be increased, a considerable step forwardwould be achieved within this particular art.

Continuing with the comments on drawbacks and difficulties which areencountered, when using bars with helicoidal ribs, it is to be recalledthat when such bars are embedded in a concrete member which is subjectto load, that there is a tendency of such bar to move with regard to theconcrete according to an axis which is coaxial with the axis of thehelicoid which is defined by the rib. Because of this, the anchorage ofsuch bar in a concrete member is not the optimum.

Rods of the diameters hereinabove mentioned, and used in reinforcedconcrete structures are generally not subject to any improvement processprior to be used; as a matter of fact in most cases just cylindricalrods are used.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a process for producing such rods with an increased capabilityof adhesion and a higher yield point than is the case in the orthodoxuntreated rods. To achieve such a result, the invention is based on theconcept, that for increasing the yield point, bearing in mind that it isanti-economical to subject individual rods to a torsional process it isnecessary to submit a strip in a first step to cold compacting, tothereby reduce the cross-sectional area of such a strip. The resultingmember has already a higher yield point. This member is then subject toa second-step which is a shaping process without generating anytorsional stress on the member, in order to obtain on the periphery ofsuch member small stud like anchoring projections, which increase thecapability of adhesion.

During the shaping process step, part of the metal of the member ismoved, while the rest remains substantially unaltered. From the lastmentioned unaltered portions, the anchoring projections are formedwithout substantially changing the metallographic structure of suchportions. To be more specific, the unaltered portion will include thecore of the rod, as well as the anchoring projections and which areprecisely those which have to resist the more outstanding stresses, oncethe resulting rod is embedded in a concrete member, which is subject topertinent loads.

The stud-like anchoring projections are preferably aligned and spacedapart among themselves in such a manner that they do not define ahelicoidal path along the rod, whereby a better anchorage is achieved.In addition, the separation of the studs is selected in relationship tothe size of the granules of the pertinent components of the concrete,such as sand, stone or gravel which may at least partially enter in thespaces defined in between such studs.

In addition, since the resulting rods are to be bent into the mostvariable shapes, special care is taken, that no sharp angles are formedat the portion where the studs merge into the core of the rod.

Preferably the studs are grouped in series.

The rods manufactured in accordance with the present invention areparticularly used for stirrups, clamps, and the like; for tyingreinforcement bars; they are also used in small concrete beams, slabsand road structures, as well as in prefabricated concrete members ofsmall size.

The present invention relates thus to a process for producing a metalrod, preferably of iron, with a high yield point and pronouncedcapability of adhesion, for reinforced concrete and the like, comprisingthe steps of subjecting to cold compacting a metal strip, in order toreduce its cross-sectional area and increase the yield point of themetal constituting it, to produce a member having a substantiallyconstant cross-section defining intersecting major and minor axes, andthereafter applying, on opposite peripheral portions of the member whichincludes said major axis, the necessary pressure to shift part of themetal from said opposite peripheral portions, and to form spaced apartstuds by maintaining in longitudinally spaced apart zones the remainingpart of the metal in said opposite peripheral portions, said studsdefining the means to increase said capability of adhesion.

Within the inventive concept in relationship to the process, it is to bepointed out that there are other features, such as that the process is acontinuous one; that the metal strip which defines the starting materialfor the process has a rectangular cross-sectional area and that thelatter can be obtained by cutting a sheetlike metal plate of suitablethickness into a plurality of parallel strips.

The invention is likewise concerned with a metal rod which has asubstantially cross-sectional circular area having a diameter not largerthan about 8 mm and where diametrically opposite peripheral zones areprovided with staggered projecting studs which have substantially thesame high yield point as the material of the rod existing between saiddiametrically opposite peripheral zones which define the core of saidrod. The studs are preferably staggered in series of several studs alongthe rod.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate theinterpretation of the present invention, reference will now be made, byway of example to several embodiments, in relationship to theaccompanying drawings, wherein:

FIG. 1 is a schematic perspective view, showing a hot rolled metal sheetroll which is being cut into parallel strips.

FIGS. 2, 2a, 3, 4 and 5 show schematic perspective views of severalstations of a machine which enables to carry out the continuous processin accordance with the present invention.

FIGS. 2b, 3a and 5a are longitudinal sections through the pairs ofrollers respectively shown in FIGS. 2a, 3 and 5.

FIG. 5b is a perspective view of a roller of the pair of rollers shownin FIGS. 5 and 5a.

FIGS. 6 to 12 are respective cross-sections according to lines VIVI,VII-VII, VIII-VIII, lX--IX, X--X, XI-XI and XII-XII which are shown inFIGS. 2 to 5, and in FIG. 12, there is in addition shown in dottedlines,the cross-sectional area of the member of FIG. 11.

FIG. 13 is an enlarged cross-sectional detail of a portion of the rollershown in FIG. 5b.

FIG. 14 is a portion of a finished rod, in accordance with the processof the present invention.

FIG. 15 is a schematic illustration of the process to which the startingmaterial is to be subject, according to an arrangement which is analternative embodiment with regard to the one shown in FIGS. 2 to 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, ametal sheet roll l is shown, from which parallel strips 2 are cut bymeans of a plurality of cutting disks 3. Upon unwinding roll 1, thepertinent portion of the unrolled flat metal sheet defines an upper face4 and a lower face 5. The resulting cut strips 2 will also have each anupper face 4 and lower face 5 the lengths of which are larger than thethickness of the sheet member. These strips 2 are then individuallywound on drums, one of which is partially shown in FIG. 2 and identifiedby reference numeral 6; the winding is so performed that the upper andlower faces 4,5 become side faces. Referring now to FIG. 6, a section ofstrip 2 is there shown with the side faces 4,5, which are substantiallyparallel among themselves, and end faces 7,8, which are slightlyirregular due to cutting of the disks 3.

One of the fundamental steps, according to the process of the presentinvention, resides in cold compacting these strips 2,to thus increasethe resulting yield point. Tests have shown that such compacting is bestachieved by applying pressure on the end faces 7,8. However, if suchcompacting would be directly performed on the irregular end faces 7,8,it would not be possible to achieve a uniform distribution of thecompacting load. On theother hand, undue hardening of the metaldefiningthe end faces 7,8 when subject to compacting, should be avoided, sinceotherwise the later steps of the method of the invention could not besuccessfully performed.

Accordingly, a solution had to be found to transform the irregular endfaces 7,8 into small ones, which enable to apply thereon uniformlydistributed compacting loads. To this end, a pair-of idle shapingrollers 9,10 (FIG. 2a) mounted on pertinent shafts 11,12, onlyschematically shown, are provided to convert the substantiallyrectangular cross-sectional area (FIG. 6) into a cross-sectional area 13having the shape shown in FIG. 7 and to which reference will bemadelater on. The two shaping rollers 9,10 have preferably the samediameter, for instance mm. Since the structure of both rollers 9,10 isidentical, reference will now be made only to roller 9. Roller 9 has ashaping channel 14 defined by two substantially parallel, side walls 15and a concave-shaped bottom wall .16. The cross-sectional area ofchannel 14 is substantially equal to half of the cross-sectional area 13(FIG. 7).

Strip 2 is fed from drum 6 and before entering the shaping station ofrollers 9,10, the faces 4,5,7,8 are coated with a lubricant. Saidcoating may be performed in many well-known manners, for instance, bymeans of a sprayin-gun or passing said strip through a lubricantcontaining container, or as schematically shown in FIG. 2a, by passingsuch strip through a pair of felt cylinders 17,18 to which lubricant issupplied by.means of a dosifier 19.

Rollers 17,18 are rotatably mounted on a pivoted support 20, which dueto spring 21 maintains rollers 17,18, in contact with the faces of thestrip 2. The, lubricant used may, for instance, be a SAE 60 oil. Theobject of such lubrication is to enable the shaping of strip 2 throughrollers 9,10 with a minimum load or pressure.

If FIGS. 6 and 7 are compared, it may be appreciated that the-portionsof material which are present in the corners defined by faces 4 and 7; 7and 5; 5 and 8; and

8 and 4, are moved, upon strip 2 passing through the shaping station9,10, whereby the distance between the;-

the distance existing between faces 4 and 5 of strip 2,

shown in FIG. 6. It is because of this, that the distance which existsbetween the side walls of the channel,

14, is slightly larger than that which exists between the faces 4 and 5,in order to permit the movement of such material and furthermore toobtain by means of the bottom-walls 16 the shape of faces 7' and 8'.

The load which is applied to rollers 9 and 10 is the minimum necessaryto carry out the shaping and is approximately 1,000 kg, if rods ofapproximately 5 mm diameter of the type used in reinforced concrete, areemployed.

The shaping step up to here described, is not an absolutely necessaryone, although convenient, in order to carry out the following compactingstep in an optimum way.

To facilitate the explanation of the following steps'of the process ofthe invention, in the cross-sectional area 13 illustrated in FIG. 7, amajor axis 22 and a minor axis 23 are shown, where the length of themajor axis 22 is approximately equal to the distance which existsbetween the end faces 7 and 8 (FIG. 6). The axes 22 and 23 cross eachother.

In order to carry out the compacting step, the strip is now passedthrough a compacting station, consisting of a pair of compactingdriven-rollers 24,25. Actually, the compacting station 24,25 is coaxialwith the shaping station 9, 10 and acordingly, the drawing should beinterpreted in this manner. The compacting channels of rollers 24, haveeach seen in cross-section a semielliptical shape so that, as shown inFIG. 3a, the facing portions of the rollers 24,25 define an ellipticalspace 26. Conveniently, the upper roller 24 has a slightly largerdiameter (237 mm) than the lower roller 25 (235 mm), so that uponrotating both with the same number of revolutions (for example 72r.p.m.) there is a tendency of the strip member to exit such station bydownwardly curving, so that by locating at the outlet of the compartingstation 24,25 a suitable discharge table 27 (FIG. 3) the resulting rodis rectilineally discharged from the lower roller 25. In the compactingstation 24,25, a considerable pressure or load is exerted on the convexend faces 7, 8' (FIG. 7) to transform the strip 2 into a rod having anelliptical cross-section and where the compacting is such, that themajor axis 22 (FIG. 7) is transformed into the minor axis 28 (FIG. 8)and the minor axis 23 (FIG. 7) is transformed into the major axis 29(FIG. 8). This rather substantial transformation implies a reduction inthe cross-sectional area of the strip, transforming it into a rod 30which is metallographically modified by considerably increasing itsyield point. In the example which is being described, a load ofapproximately 2,200 kg is applied, which, with regard to the loadapplied at the shaping station 9,10 (1,000 kg), represents an increaseof 120%.

Thus a rod 30 is achieved, the yield point of which has reached thedesired value, but which rod is still lacking suitable anchoring means,which, in accordance with the concept of the present invention have tobe produced without altering the physical features of the rod, at leastin those portions which correspond to the future anchoring means and inthe core of the rod, because these are the more important portions ofthe rod when subject to stress in a concrete member, in which it is tobe embedded.

The anchoring means are merely small studs 31, such as shown in FIG. 14,where a finished rod 32 is shown. These studs 31 are present in seriesof three uniformily spaced apart studsand each series, in turn, isspaced apart from the next series in a distance which is larger 7 thanthe distance which exists between successive studs of the same series.In addition, the series of studs are aligned along diametricallyopposite generators and one series of studs of one generatrix faces aninterserial space of the other generatrix. As to the particular shape ofthe studs, reference will be made thereto later on.

The resulting rod 32 should have, apart from the studs 31, approximatelya circular cross-section (FIG. 12).

In order to achieve all these features, it is convenient to shape thestuds 31 in the zones corresponding to the ends of the major axis 29. Inthe embodiment which is being described, the elliptical rod 30, with itsmajor axis 29 in a horizontal position, as shown in FIG. 9, is passedthrough a series of orienting rollers 33, 34; 35,36; 37,38 (FIG. 4), inorder that the rod is turned, so that its major axis 29 becomesvertical. To carry out this reorientation, without exerting a permanenttorsional stress on the rod, the pair'of rollers 33,34; 35,36;

37,38 are idly mounted on respective shafts in order that theirpertinent channels will only carry out a guiding action. The first pairof rollers 33,34 supports the rod 30 with the major axis 29 inhorizontal position (see also FIG. 9). The second pair of rollers 35,36supports the rod 30 with its major axis 29 in a sloped position (forinstance 45; FIG. 10) and the last pair of rollers 37,38 supports therod 30 with its major axis 29 in upright position (FIG. 11).

This rotation of the rod is merely performed to be able to feed the rodinto an existing rolling mill, where only the conventional rollers haveto be replaced by rollers 39,40 to be described later on. Obviously, theguiding rollers 33,34; 35,36; and 37,38 shown in FIG. 4 are coaxiallyarranged with the compacting station 24,25.

Reference is now made to FIG. 12, which shows in dotted lines, theelliptical cross-section ,of rod 30 in upright or vertical position,similar to FIG. 11. Rod 30 is now passed through the stud shapingstation consisting of a pair of driven rollers 39,40 (FIG. 5) arrangedbehind the guiding rollers, shown in FIG. 4. .These rollers 39,40 haveto rotate at a higher speed (for instance 83 r.p.m.) than the drivenrollers 24 and 25.

Also in the stud shaping station, the upper roller 39 has a largerdiameter than the lower roller 40, for example 239 mm and 235 mm,respectively, in order to achieve the same result as in the compactingstation 24,25. In order not to overload the drawing, no discharge tablehas here been shown, but a table similar to table 27, shown in FIG. 3,is also used.

Each roller 39,40 is as such of similar structure and each one has achannel 41 (FIG. 5b) which in general has a semi-circular cross-section,and which in their bottom walls have pluralities of holes 42, arrangedin series to produce the already mentioned studs 31.

Obviously, the holes 42 of the upper roller 39 will be staggered withregard to bhe holes of the lower roller 40, to achieve thus thedistribution of the studs 31, as shown in FIG. 14.

Referring now to FIG. 13, where one of the holes 42 is shown, it may beseen that the latter has a cap-shaped bottom portion, actually aspherical sector bottom portion with a radius 43 and the opening ofwhich broadens to establish thus a linking zone with the walls definingthe actual channel 41, defined by radius 44. It may be appreciated thatthis broadening zone, in this embodiment is defined by radii 45, thecenters of ourvature 46 of which are located outside the cavity definedby channel 41, while the centers of curvature 47 and 48 of the cap andthe channel, respectively are located within the pertinent cavities.Thus, studs may be formed, the side walls of which join in a continuouscurve like manner with the cylindrical surface of the rod.

Returning now to FIG. 12, it may be seen, that the elliptical rod 30,due to the fact that it has been previously orientated, may enter theinlet of the channel 49 defined by the rollers 39,40 with its major axis29 in upright position, so that the necessary pressure may now beapplied on the opposite peripheric portions'of such body, in which themajor axis 29 is located, in order to move a portion of the metal ofthese opposite peripheric portions by maintaining only the metal of thepertinent mid portions and which are to form the studs 31 while the restof the metal is outwardly moved to increase the portion corresponding tothe minor axis 28 and to thus transform the elliptical section 30 into acircular section 32' having the studs 31.

Referring again to FIG. 12, it may be seen that the zone of the finishedrod 32, which is inscribed in a dotted line, is practically not subjectto metallographic tranformations during the passage through rollers 39and 40 and that zone is the one which defines the core and the studs ofthe finished rod 32.

- Thus, a product is achieved having a high yield point and newanchoring means where these means and the adjacent zones of the core arenot subject to undue pressure during the transformation which takesplace when the rod is passed through rollers 39 and 40, to produce thestuds. The load which is applied to rollers 39 and 40, in the examplegiven, is approximately 3,300 kg. In other words, there is an increaseof approximately 50% with regard to the load applied at the compactingstation 24,25. Although in absolute values, there is an increase of 50%,it should not be overlooked that in relative values, this increase isconsiderably smaller, because when the strip enters the shaping station9, 10 it has, for instance, a Rockwell hardness of -40, and upon leavingsaid station, a Rockwell hardness of B-55 and upon said strip enteringthe compacting station 24,25 it still has the same hardness, i.e.Rockwell B-55; when said strip leaves the compacting station as a rodits hardness has been increased to B-65.

In other words, if the hardness at the inlet of the shaping station 9,10 is compared with the hardness at the outlet of the compacting station24, 25, it will be seen that there is an increase from 40 to 65 RockwellB. On the other hand, upon entering the rod to the studshaping station39, 40, it has, as already stated, a hardness of Rockwell B-65 and uponleaving the latter its hardness has only slightly increased, namely toRockwell B-70. This means that the pressure increase which is applied atthe stud-shaping station is the necessary minimum in order to be able toproduce the studs as explained, bearing in mind that the material thatis there used has a hardness of Rockwell B-65.

In FIG. 5, a cutter 50 is schematically shown which may cut the rodwhich leaves station 39, 40 into rod members having a predeterminedlength.

In FIG. 15, a similar arrangement is shown with regard to the onedescribed in connection with FIGS. 2a

to 5; the difference resides in that in the embodiment of FIG. 15 noguiding rollers of the type shown in FIG. 4, are used, and on the otherhand, the stud-forming station consists of a pair of rollers 39' and 40'arranged according to the horizontal. Apart from this fact, the samereference numerals have been used as in the prior Figures, so that itdoes not become necessary to redescribe the entire arrangement.

Although several embodiments of the invention have been illustrated anddescribed in detail, it is to be expressly understood that the inventionis not limited thereto. Various changes can be made in the design andarrangement of the parts, without departing from the spirit and scope ofthe invention, as the same will now be understood by those skilled inthe art.

I claim:

1. A process for producing a metal rod having a high yield point andgood adhesive properties for use with reinforced concrete or the like,comprising the steps of:

producing an elliptical rod having intersecting major and minor axes bysubjecting a metal strip to cold compacting in order to reduce thecross-sectional area thereof and to increase the yield point of themetal constituting said elliptical rod;

applying pressure to said elliptical rod at peripheral locations thereoflocated at opposite ends of said major axis;

allowing a portion of the metal at said locations to shift toward otherperipheral locations of said rod, said other peripheral locations beingat the opposite ends of said minor axis thereby increasing the amount ofmetal located at said other peripheral location while simultaneouslymaintaining another portion of the metal of said rod unshifted andsubstantially free of metalographic transformation, said another portionforming a core and studs and being located adjacent said major axis, theshifting of said material causing studs to be formed out at saidperipheral locations while said shifted material transforms saidelliptical rod to a circular rod having studs thereon.

2. Process according to claim 1, comprising the previous steps ofcutting longitudinal strips from a sheet member to define strips havingeach a rectangular cross-section, where the sides of minor lenght arethe cut faces and then shaping these cut faces to transform them intouniform surfaces, and that prior to that shaping step, each strip iscoated with a lubricant, that after the shaping step a compactingpressure is applied on said uniform surfaces, thereby carrying out saidcold compacting, whereby the substantially rectangular section, having amajor axis and a minor axis, which cross each other, is transformed intoan elliptical section, in such a manner that the major axis of therectangular section becomes transformed into the minor axis of theelliptical section and the minor axis of the rectangular section becomestransformed into the major axis of the elliptical section.

3. Process according to claim 2, wherein the compacting step is carriedout by moving the strip through a pair of compacting rollers.

4. Process according to claim 3, wherein the shaping of the cut faces,the compacting step for transforming the rectangular section into anelliptical section and the shaping of the studs is carried out in acontinuous and successive manner.

5. Process according to claim 1, wherein the studs are produced inaligned series along two diametrically op- 10 in turn, is spaced apartfrom the next series in a distance which is larger than the distancewhich exists between successive studs of the same series.

7. Process according to claim 1, wherein said studs have side wallswhich merge by means of a continuous curve into the peripheral surfaceof said rod.

1. A process for producing a metal rod having a high yield point andgood adhesive properties for use with reinforced concrete or the like,comprising the steps of: producing an elliptical rod having intersectingmajor and minor axes by subjecting a metal strip to cold compacting inorder to reduce the cross-sectional area thereof and to increase theyield point of the metal constituting said elliptical rod; applyingpressure to said elliptical rod at peripheral locations thereof locatedat opposite ends of said major axis; allowing a portion of the metal atsaid locations to shift toward other peripheral locations of said rod,said other peripheral locations being at the opposite ends of said minoraxis thereby increasing the amount of metal located at said otherperipheral location while simultaneously maintaining another portion ofthe metal of said rod unshifted and substantially free of metalographictransformation, said another portion forming a core and studs and beinglocated adjacent said major axis, the shifting of said material causingstuds to be formed out at said peripheral locations while said shiftedmaterial transforms said elliptical rod to a circular rod having studsthereon.
 2. Process according to claim 1, comprising the previous stepsof cutting longitudinal strips from a sheet member to define stripshaving each a rectangular cross-section, where the sides of minor lenghtare the cut faces and then shaping these cut faces to transform theminto uniform surfaces, and that prior to that shaping step, each stripis coated with a lubricant, that after the shaping step a compactingpressure is applied on said uniform surfaces, thereby carrying out saidcold compacting, whereby the substanTially rectangular section, having amajor axis and a minor axis, which cross each other, is transformed intoan elliptical section, in such a manner that the major axis of therectangular section becomes transformed into the minor axis of theelliptical section and the minor axis of the rectangular section becomestransformed into the major axis of the elliptical section.
 3. Processaccording to claim 2, wherein the compacting step is carried out bymoving the strip through a pair of compacting rollers.
 4. Processaccording to claim 3, wherein the shaping of the cut faces, thecompacting step for transforming the rectangular section into anelliptical section and the shaping of the studs is carried out in acontinuous and successive manner.
 5. Process according to claim 1,wherein the studs are produced in aligned series along two diametricallyopposite generators of the rod, having a circular cross-sectional area,the interserial space of adjacent series of studs is larger than thespace existing between adjacent studs of the same series, and eachseries located along one generatrix generally facing the interserialspace of two adjacent series of the other generatrix of said rod. 6.Process according to claim 5, wherein each series has three uniformlyspaced-apart studs and each series in turn, is spaced apart from thenext series in a distance which is larger than the distance which existsbetween successive studs of the same series.
 7. Process according toclaim 1, wherein said studs have side walls which merge by means of acontinuous curve into the peripheral surface of said rod.